How do I honor User Name CSS when viewing detailed outcomes?

Rich username CSS only comes into play where the xen username helper adds the "rich" attribute to the helper and sets it to true.

HTML:

<xen:username user="$user" rich="true" />

I use them in a few specific targeted places in Sportsbook, however, I don't use them everywhere.

You'd have to search through the templates that you want to display RICH usernames and add the rich="true" to the username helpers. HINT: search for '<xen:username' (without the tick marks) and set the addon to Sportsbook. That will pull up the 32 Sportsbook templates that use the username helper.